Subsea oil and gas production wells typically require hydraulic power for opening valves and chemical treatment to help ensure the reservoir; production tubing, valves and pipelines remain in optimum condition for well flow and pressure integrity. These services are typically delivered from a host facility to a subsea well via an umbilical. Where multiple wells are served from a single umbilical, the hydraulic and chemical services must be distributed among them, either within a termination unit directly connected to the umbilical, often called an umbilical termination assembly (UTA), or within a distribution unit, often called a subsea distribution unit (SDU) or hydraulic distribution manifold (HDM), connected to the umbilical termination via jumpers, usually called flying leads. Subsea connection of the hydraulic and chemical lines are made using specialized hydraulic connectors, often referred to as junction plates, stab plates or multi-quick connector (MQC) plates, in which one or more pairs of hydraulic couplings are mated together simultaneously using a mechanical mating mechanism.
Additionally, it is possible to distribute chemicals from a single umbilical tube to multiple subsea injection points via the use of specialized subsea valves, often referred to as chemical injection metering valves (CIMV) or chemical throttling valves (CTV). These valves are typically pre-installed onto subsea equipment prior to being installed or deployed.